Elastomers are one of the principal ingredients of a chewing gum base and thus in turn one of the principal ingredients of a final chewing gum product. the final chewing gum, although there are some systems which are capable of producing a final chewing gum product in one continuous process.
A typical chewing gum base includes one or more elastomers, one or more fillers, one or more elastomer solvents, plasticizers and, optionally, polymers, waxes, emulsifiers and miscellaneous colors, flavors, sweeteners, acids and anti-oxidants. Due primarily to the difficulty in melting and dispersing the elastomers homogeneously among the other gum base ingredients, gum base manufacture has typically been a tedious and time-consuming batch process. Sigma blade batch mixers are typically used for this conventional process.
In general, a chewing gum composition typically comprises a water-soluble bulk portion, a water-insoluble chewing gum base portion, and typically water-insoluble flavoring agents. The insoluble gum base generally comprises elastomers, elastomer solvents, plasticizers, waxes, emulsifiers, resins, fats and inorganic fillers. The water-soluble portion dissipates with a portion of the flavoring agent over a period of time during chewing. The gum base portion is retained in the mouth throughout the time that the product is chewed.
The batch method of producing chewing gums has long been considered the standard for producing chewing gums, as well as gum bases, on a commercial scale. The batch processes tend to be labor-intensive and produce chewing gums of varying consistency. Once the gum base is formed, emulsifiers, such as lecithin, softeners, such as glycerin or Wesson oil, corn syrup and bulking agents, such as sugars or sugar alcohols, are added to the molten mass. Later, flavorings, such as flavor oils and/or spray-dried flavors, and sweeteners (and/or acids) are added while mixing is continued until a homogeneous mass is achieved. The chewing gum mass is then cooled and later rolled, scored, and wrapped into the final product.
Where the gum base is processed separately, typically the molten gum base batch after mixing is emptied into coated or lined pans, or pumped to other equipment such as holding tanks or a filling device, then extruded or cast into shapes, and allowed to cool and solidify, before being ready for use in chewing gum.
Various efforts have been undertaken to try to simplify and reduce the time required for gum base and chewing gum manufacture, as well as to prepare gum base and gum products which have improved commercially acceptable properties. For example, the use of continuous extruders to make a final chewing gum product are shown in U.S. Pat. No. 5,135,760 to Degady et al., U.S. Pat. No. 5,045,325 to Lesko et al., and U.S. Pat. No. 4,555,407 to Kramer et al.
Also, there are several processes in the art for continuously producing a chewing gum base with the use of a continuous extrusion machine. These are disclosed, for example, in U.S. Pat. No. 5,419,919 to Song et al., and U.S. Pat. No. 5,486,366 to Song et al.
The continuous gum base processes and final chewing gum product processes disclosed in these patents typically utilize a continuous extrusion machine, such as a twin-screw extruder. These extruders can be co-rotational, counter-rotational, intermeshing or tangential twin screw extruders, depending on the requirements and purposes of the system involved. Those extruders typically have several feed inlets where the ingredients are added separately. Continuous extrusion machines which can be used for producing a chewing gum base or a final chewing gum product, or both, include extruders from Japan Steel Works, Leistriztz, Werner & Pfleiderer Corp., Buss Mfg. Co., WLS, Togum and Baker Perkins.
Elongated screws inside the barrels of the extruders are equipped with different types of elements. While different equipment manufacturers make different types of screw elements, the most common types include conveying elements, compression elements, reverse conveyance elements, homogenizing elements such as shearing disks and toothed elements, and kneading disks and kneading blocks. These various types of elements, and other elements typically used in extruding machines, especially twin screw extruders, are well known in the art and commercially available. The elements are often specifically designed for the particular type of extruders utilized. Elements intended for similar functions will vary in design depending on the type of extruder for which they are intended.
Whether a batch-type processor or a continuous extruder-type processor is used to produce the chewing gum and gum base products, it is important to provide the various ingredients for these products in the best form and condition. This improves the speed and efficiency of the final processing. In this regard, ingredients such as the fillers, elastomers, plasticizers, oils, waxes, and the like, often require special handling or preparation prior to being included in the batch or extrusion process.
Preparation of the ingredients is especially important where continuous extrusion processing is utilized. The ingredients supplied to the continuous extrusion apparatus are preferably provided in the optimum size, shape, and temperature for ease of handling, insertion and intermixing with the other ingredients in the extruder. Also, due to the properties of some of the various ingredient materials, it is necessary to pre-prepare or pre-blend them in order to allow them to be inserted in the extruder in the best possible condition.
As indicated, one important component of a gum base is the elastomeric portion which can include natural elastomers, synthetic elastomers, or combinations thereof. This element of the gum base is important in that it provides the insoluble body with resiliency to recover from deformation caused by chewing. In preparing gum base, it is important that other components which are included in the base composition to effect various characteristics of the resulting chewing gum, be thoroughly mixed with the elastomeric portion so that the entire gum base product will retain proper resiliency as a homogeneous phase.
Solid elastomers suitable for use in chewing gum bases and final chewing gum products include synthetic gums or elastomers, such as butadiene-styrene copolymer, polyisobutylene, and isobutylene-isoprene copolymer, as well as natural gums or elastomers, such as chicle, natural rubber, jelutong, balatea, guttapercha, lechi, caspi, sorva, or mixtures thereof.
In order to achieve a ho mogeneous phase gum base body wherein a proper resiliency is constant throughout and the product is free from lumps and other irregularities, it is necessary to provide components which are compatible with one another and as dispersed and distributed as much as possible in the materials being processed. Factors such as the affect of water-soluble components, heat, moisture, and the like, must be considered in preparing a useable gum base.
It is the general object of the present invention to provide an improved method and apparatus for the production of chewing gum products and gum base products. It is also an object of the present invention to provide improved apparatus and methods for preparation of some of the chewing gum and gum base ingredients prior to blending in order to facilitate improved final processing.
It is still another object of the present invention to provide a method and apparatus for improving the properties of elastomeric ingredients for chewing gum bases. It is another object of the present invention to provide an improved process and apparatus for breaking down, preparing, and inserting the elastomeric component of a chewing gum base into the system, particularly for use with a continuous extrusion process.
These and other objects, benefits, and advantages of the present invention are met by the following description of the invention.